Owing one myself, 12lbs evolution flywheel and act heavy duty pp with 6puck unsprung clutch. I noticed (since it is summer now) I hear tap tap tap Noise on bellhousing area on idle when I put the a/c on (when idle drops due to load). The moment I increase the rpm by 100 or disengage the clutch (pedal in) noise dissapears. Also, with a/c off all I heAr is some sort of gear roll over noise on warm (when trans oil is thinner thus absorbs less shock). Gear shifting is great, no issues.

I would like to conClude it as chatter but would like peoples opinion. Hope that it is not input shaft bearing since the conditions are different.

Some people refer chatter as 'shuderring' effect when letting your clutch out from stop. Some people refer it as noise.

 

BUmP!!

Pretty sure that there are a lot of guys here running lightweight flywheel and unsprung clutch.